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Essential Questions:
ENGAGE
It's Cyclical
You probably remember the water cycle from your school days. Water evaporates from warmer regions of the planet and is transported by Earth's winds to the colder regions where it condenses and falls as rain or snow. Sound familiar?
And you may also recall learning how the surface of the Earth is weathered and eroded by various forces over time, and that the eroded sediments are transported by wind, water and gravity where they are deposited in low lying areas, including the ocean. No surprises, right?
In our previous section, we learned a bit about how mountains are made. But we didn't discuss the fate that awaits them, as does all land above sea level.
Tall mountains - all mountains - become small mountains. It's just a matter of time. And gravity. And heat. And water. Lots and lots of water. Both liquid and solid.
In this section, we'll explore the tremendous force water in its various forms exerts on Alaska's landscapes. From vapor to rain; From glaciers to rivers; From permafrost to sea ice - the atmosphere, hydrosphere and the cryosphere may be listed separately, but each are profoundly interconnected.
And ultimately, all three must be regarded collectively in order to understand how Alaska's climate dynamics, water and ice have shaped its physical contours for millions of years - and its cultures for thousands of years.
EXPLORE
Water, Water Everywhere?
Water, water everywhere, but how much can you drink? How much of Earth's water is in the ocean? How much is fresh? How much is in the atmosphere? How much is in lakes, rivers, or underground? How much of Earth's fresh water is stored frozen as permafrost and glaciers?
Alaska's Water - A Big Drop in the Bucket
How would you estimate the planet's precious supply of water is distributed?
The Cryosphere is Here
Icy - I See Why
Our planet uses many of the same tricks that over-heated humans use to cool off. Our circulatory system is like the great ocean currents moving our excess heat to cooler places. We mist and fan ourselves, put on a white shirt and white broad-brimmed hat, or we head for the shade.
Likewise, Earth wears a white broad-brimmed polar cap that reflects radiant energy instead of absorbing it. Its raft of floating clouds create shade and its winds carry heat in the form of evaporated water away to cooler places. Same-same.
Along with the hydrosphere and lithosphere and atmosphere, we also have a region of Earth called the cryosphere that is dominated by ice. It's a relatively new term in our common language, but it's understanding is important as we learn more about the separate, but connected variables influencing climate in Alaska for millions of years.
Because heat always moves from where it's hot, to where it's not, we can suffice it to say Earth's icy poles provide the very desirable function of disposing excess planetary heat absorbed at lower latitudes. Sort of like Earth's air conditioner.
EXPLORE
Teachers Domain
This brief TD video describes the role of the cryosphere in regulating Earth's climate, as well as some of the dynamics observed in the sea ice and glaciers of the region.
Earth's Cryosphere: The Arctic
EXAMINE
EXTEND
ENGAGE
Imagine a mountain valley catching the moisture that falls within its boundaries and funnels it down into a lake sprawling across a low lying area. When the precipitation exceeds the capacity of the lake, it spills over into a river that flows down toward sea-level. Sounds reasonable and familiar. We've all seen it.
But what if the moisture that falls in the high mountain valley is snow that doesn't melt each spring? What's different? Erosion and sedimentation processes notwithstanding, any glaciologist will tell you, not too much is different -- if you've got the time to watch.
Snow falling at high elevations probably evaporated from the surface of the tropical ocean no more than a couple of weeks prior. This accumulating young snow compresses under its own increasing weight over time turning into dense, clear ice.
When the lake of ice (ice field) fills to overflowing, the plastic river of ice flows out of the confines of its upper reaches and meanders slowly and massively downhill, grinding and eroding its own deep valley along the way on its journey to the sea.
Inland glaciers flow out of high mountain valleys until they reach lower, warmer elevations and liberate their solid water and sediments into lakes and rivers off to find the sea. Alaska's coastal mountain ranges host many glaciers that surrender their centuries old cache of water directly into the ocean as ice--tidewater glaciers.
Whether indirectly by river or directly by glacier, water is constantly rejoining the ocean for the first time in many, many years. And it's doing so at a rate that presently exceeds the rate at which it is returned to the mountains as snow.
And like a river, a glacier's rate of flow is determined largely by the amount of precipitation accumulation that fills its reservoirs . Advancing glaciers are driven by accumulation rates that exceed its melting, or ablation, rate.
The Great Recession
Unlike liquid rivers, glaciers frequently change phase (melt) abruptly as they descend to warmer elevations. Glaciers that melt faster than they advance are called receding glaciers. This dance between accumulation and ablation, advance and retreat, is expressed over time as a glacier's mass balance.
Most glaciers have been receding since the LGM. But ice sages studying the mass balance of glaciers world-wide have noted recent acceleration in the ablation rates of glaciers, indicating overall increased rate of reduction in glacier mass balance.
Lyrical Landscape Lexicon
Left behind the receding ice are the curious landforms unique to the forces of glaciers: esker, drumlin, kettle, moraine, cirque, tarn, kames, varve and arete are just part of the lyrical lexicon of glaciologists describing specific processes and formations that result from the advance and retreat of glaciers. You might be surprised by how many of these post glacial landscape features are part of our common geography.
From the Great Lakes to Cape Cod. From Long Island to Lituya Bay, each is a geologically recent product of the work of glaciers. And each was settled for the first time by the earliest north Americans shortly after the ice melted.
EXPLORE SOME MORE....
Teachers' Domain
Earth System-Ice and Global Warming
EXAMINE
EXTEND
Extreme Ice Survey
Glaciers are often compared to rivers in terms of their motion, but to most of us they look solid and static. But what if you could speed-up time?
That's just what the scientists at the Extreme Ice Survey did by placing remote cameras focused on glacial landscapes and leaving them for more than a year. What emerges in the compressed sequence of images is the fluid motion of ice.
Visit the Extreme Ice Survey website and watch a time lapse Vimeo of the Mendenhall Glacier during the 16 months between May 2007 and September 2008.
Visit the USGS - Alaska Glacier Repeat Photography Project. It's an engaging collection of recent and old photographs contrasting many of Alaska's Glaciers over time.
ENGAGE
We are told that as ice in our cold polar regions melts, sea-level increases as the ocean takes up the extra water. True enough--in part.
But as it turns out, the effects of melting ice depends very much on where the ice is located, whether on land or sea. And because so much ice was stored on land as glaciers, sea level was hundreds of feet lower during the last ice age, creating the Bering Land Bridge between northern Asia and North America
And even though most of North America lay under thousands of feet of ice from Anchorage to New York, much of central and a vastly more western Alaska harbored great ice free plains sandwiched between the towering ice fields and glaciers stretching to the east and south.
EXPLORE SOME MORE....
Lower sea level at the time allowed the migration of all kinds or organisms between the northern continents. Great wooly mammoths and short-faced bears were among the local Pleistocene fauna here to greet early humans wandering the great ice free plains sandwiched between towering ice fields.
CLICK HERE to see an excellent interactive Alaska PaleoGlacier Atlas showing the extent of Alaska's glaciers over time.
CLICK HERE to visit the NPS site, Bering Land Bridge.
ENGAGE
Seasonal Terrestrial Ice--Rivers & Lakes
Besides glaciers, other terrestrial surface ice includes seasonal ice on lakes and rivers. The thickness of ice and the time of year at which lakes and rivers freeze and thaw is part of the seasonal cycles that shape the land and the behaviors of those that use them.
EXPLORE
YouTube
Breaking Up is Hard to Do
Captured by regular folks with video cameras, these YouTube videos give you an idea of what annual river ice break-ups are all about.
Check out one or all.
Because these icy soils remain frozen year-round, we call them permafrost. But just how permanent is permafrost? And, is permafrost a sleeping giant problem?
Every year, the shallow surface, or active layer, in permafrost zones thaws in the summer allowing a brief window for plants to grow, die and partly decompose. But because freezing inhibits microbial decomposition of ancient plant matter, decomposition is very slow work in cold climates.
The non-decomposed material left over each year accumulates in an every-growing massive biomass store of frozen carbon. This is good if you want to take carbon out of the atmosphere--as long as it stays frozen.
Pingo, polygon ice wedges, thermokarst, and solifluction not yet in your daily vernacular? Permafrost science has its own fun language and heroes. Ever seen Tunnel Man? It's time to explore the weird world of permafrost.
EXAMINE
Essential Questions:
- How are Alaska's natural systems interconnected?
- How have Alaska's natural systems changed over time?
- How does digital information change our understanding of natural systems?
- How does knowledge of natural systems inform our understanding of cultural systems?
- How does knowledge of natural systems relate to the roles of educators?
 |
| A deeply carved fjord in Glacier Bay - C.Good |
You probably remember the water cycle from your school days. Water evaporates from warmer regions of the planet and is transported by Earth's winds to the colder regions where it condenses and falls as rain or snow. Sound familiar?
And you may also recall learning how the surface of the Earth is weathered and eroded by various forces over time, and that the eroded sediments are transported by wind, water and gravity where they are deposited in low lying areas, including the ocean. No surprises, right?
In our previous section, we learned a bit about how mountains are made. But we didn't discuss the fate that awaits them, as does all land above sea level.
 |
| Hanging glacier, Glacier Bay. C.Good |
In this section, we'll explore the tremendous force water in its various forms exerts on Alaska's landscapes. From vapor to rain; From glaciers to rivers; From permafrost to sea ice - the atmosphere, hydrosphere and the cryosphere may be listed separately, but each are profoundly interconnected.
And ultimately, all three must be regarded collectively in order to understand how Alaska's climate dynamics, water and ice have shaped its physical contours for millions of years - and its cultures for thousands of years.
EXPLORE
Water, Water Everywhere?
Water, water everywhere, but how much can you drink? How much of Earth's water is in the ocean? How much is fresh? How much is in the atmosphere? How much is in lakes, rivers, or underground? How much of Earth's fresh water is stored frozen as permafrost and glaciers?
Alaska's Water - A Big Drop in the Bucket
How would you estimate the planet's precious supply of water is distributed?
- CLICK HERE to explore some USGS educational resources.
I Only Have Ice For You
How much fresh water on Earth is stored in glaciers? How would you estimate the distribution of glaciers on Earth? In Alaska?- CLICK HERE for more great USGS resources.
The Cryosphere is Here
Icy - I See Why
Our planet uses many of the same tricks that over-heated humans use to cool off. Our circulatory system is like the great ocean currents moving our excess heat to cooler places. We mist and fan ourselves, put on a white shirt and white broad-brimmed hat, or we head for the shade.
Likewise, Earth wears a white broad-brimmed polar cap that reflects radiant energy instead of absorbing it. Its raft of floating clouds create shade and its winds carry heat in the form of evaporated water away to cooler places. Same-same.
Along with the hydrosphere and lithosphere and atmosphere, we also have a region of Earth called the cryosphere that is dominated by ice. It's a relatively new term in our common language, but it's understanding is important as we learn more about the separate, but connected variables influencing climate in Alaska for millions of years.
Because heat always moves from where it's hot, to where it's not, we can suffice it to say Earth's icy poles provide the very desirable function of disposing excess planetary heat absorbed at lower latitudes. Sort of like Earth's air conditioner.
EXPLORE
Teachers Domain
This brief TD video describes the role of the cryosphere in regulating Earth's climate, as well as some of the dynamics observed in the sea ice and glaciers of the region.
Earth's Cryosphere: The ArcticEXAMINE
- What are some roles of the cryosphere in regulating global climate?
- How are glaciers and sea ice different?
EXTEND
- What kind of snow and ice data exists for your region?
- Who in your area has an historical sense of local snow and ice dynamics?
ENGAGE
Glaciologists--Ice Sages
 |
| Mendenhall Moulin Explorer-C.Goo |
But what if the moisture that falls in the high mountain valley is snow that doesn't melt each spring? What's different? Erosion and sedimentation processes notwithstanding, any glaciologist will tell you, not too much is different -- if you've got the time to watch.
Snow falling at high elevations probably evaporated from the surface of the tropical ocean no more than a couple of weeks prior. This accumulating young snow compresses under its own increasing weight over time turning into dense, clear ice.
When the lake of ice (ice field) fills to overflowing, the plastic river of ice flows out of the confines of its upper reaches and meanders slowly and massively downhill, grinding and eroding its own deep valley along the way on its journey to the sea.
 |
| Herbert Glacier near Juneau-C.Good |
 |
| Tidewater glacier, Glacier Bay - C.Good |
And like a river, a glacier's rate of flow is determined largely by the amount of precipitation accumulation that fills its reservoirs . Advancing glaciers are driven by accumulation rates that exceed its melting, or ablation, rate.
The Great Recession
Unlike liquid rivers, glaciers frequently change phase (melt) abruptly as they descend to warmer elevations. Glaciers that melt faster than they advance are called receding glaciers. This dance between accumulation and ablation, advance and retreat, is expressed over time as a glacier's mass balance.
Most glaciers have been receding since the LGM. But ice sages studying the mass balance of glaciers world-wide have noted recent acceleration in the ablation rates of glaciers, indicating overall increased rate of reduction in glacier mass balance.
Lyrical Landscape Lexicon
Left behind the receding ice are the curious landforms unique to the forces of glaciers: esker, drumlin, kettle, moraine, cirque, tarn, kames, varve and arete are just part of the lyrical lexicon of glaciologists describing specific processes and formations that result from the advance and retreat of glaciers. You might be surprised by how many of these post glacial landscape features are part of our common geography.
From the Great Lakes to Cape Cod. From Long Island to Lituya Bay, each is a geologically recent product of the work of glaciers. And each was settled for the first time by the earliest north Americans shortly after the ice melted.
EXPLORE SOME MORE....
Teachers' Domain
Earth System-Ice and Global WarmingEXAMINE
- What different kinds of ice loss are evident?
- What factors affect a glaciers mass balance?
- How does glacial melt affect sea level?
EXTEND
Extreme Ice Survey
Glaciers are often compared to rivers in terms of their motion, but to most of us they look solid and static. But what if you could speed-up time?
That's just what the scientists at the Extreme Ice Survey did by placing remote cameras focused on glacial landscapes and leaving them for more than a year. What emerges in the compressed sequence of images is the fluid motion of ice.
Visit the Extreme Ice Survey website and watch a time lapse Vimeo of the Mendenhall Glacier during the 16 months between May 2007 and September 2008.Visit the USGS - Alaska Glacier Repeat Photography Project. It's an engaging collection of recent and old photographs contrasting many of Alaska's Glaciers over time. ENGAGE
See Ice - Sea Ice - Sea Level
Slightly overfill a glass container with ice cubes and then add water, just so that it doesn't spill over. Let's call this container the Arctic Ocean. Then watch as the ice melts. What will happen to the sea-level in your glass as the ice melts? What would your students predict? (Find the quick answer here)
Slightly overfill a glass container with ice cubes and then add water, just so that it doesn't spill over. Let's call this container the Arctic Ocean. Then watch as the ice melts. What will happen to the sea-level in your glass as the ice melts? What would your students predict? (Find the quick answer here)
But as it turns out, the effects of melting ice depends very much on where the ice is located, whether on land or sea. And because so much ice was stored on land as glaciers, sea level was hundreds of feet lower during the last ice age, creating the Bering Land Bridge between northern Asia and North America
And even though most of North America lay under thousands of feet of ice from Anchorage to New York, much of central and a vastly more western Alaska harbored great ice free plains sandwiched between the towering ice fields and glaciers stretching to the east and south.
EXPLORE SOME MORE....
Lower sea level at the time allowed the migration of all kinds or organisms between the northern continents. Great wooly mammoths and short-faced bears were among the local Pleistocene fauna here to greet early humans wandering the great ice free plains sandwiched between towering ice fields.
CLICK HERE to see an excellent interactive Alaska PaleoGlacier Atlas showing the extent of Alaska's glaciers over time.CLICK HERE to visit the NPS site, Bering Land Bridge.
- Why do does melting sea ice and glaciers have different effects on sea-level?
- How have landscapes and lifeforms changes since the Pleistocene?
ENGAGE
Seasonal Terrestrial Ice--Rivers & Lakes
Besides glaciers, other terrestrial surface ice includes seasonal ice on lakes and rivers. The thickness of ice and the time of year at which lakes and rivers freeze and thaw is part of the seasonal cycles that shape the land and the behaviors of those that use them.
EXPLORE
YouTube
Breaking Up is Hard to Do
Captured by regular folks with video cameras, these YouTube videos give you an idea of what annual river ice break-ups are all about.
Check out one or all.
Teachers' Domain
In this TD video we'll learn how students across Alaska are engaged in relevant and useful scientific measurements. They are helping to track local climate change in their region by measuring heat flux in lake ice across Alaska.
Students Measure Changes in Lake Ice and Snow
In this TD video we'll learn how students across Alaska are engaged in relevant and useful scientific measurements. They are helping to track local climate change in their region by measuring heat flux in lake ice across Alaska.
Students Measure Changes in Lake Ice and SnowFire and Ice
As most any prankster with a Bic lighter can tell you, methane is flammable. Now let's see what happens when you give grown-ups a lighter and send them out on a frozen lake.
YouTube
Click on any or all of these YouTube videos relating to the relationship between lakes and methane. Some are pro and some are not.
YouTube
Click on any or all of these YouTube videos relating to the relationship between lakes and methane. Some are pro and some are not.
ENGAGE
Permafrost--A Sleeping Giant
Glaciers are easy to observe and monitor. They are right out in the open. But an enormous quantity of solid water is found just underground over much of the surface of North America.Because these icy soils remain frozen year-round, we call them permafrost. But just how permanent is permafrost? And, is permafrost a sleeping giant problem?
Every year, the shallow surface, or active layer, in permafrost zones thaws in the summer allowing a brief window for plants to grow, die and partly decompose. But because freezing inhibits microbial decomposition of ancient plant matter, decomposition is very slow work in cold climates.
The non-decomposed material left over each year accumulates in an every-growing massive biomass store of frozen carbon. This is good if you want to take carbon out of the atmosphere--as long as it stays frozen.
How Firm a Foundation?
Ice can be very structural, as long as it remains solid. But, when sub-surface ice melts, man-made structures and natural systems are disrupted and altered. Undulating waves of surface soils and odd soggy polygonal patterns are indicators of localized changes in hydrology and the depth of permafrost.Pingo, polygon ice wedges, thermokarst, and solifluction not yet in your daily vernacular? Permafrost science has its own fun language and heroes. Ever seen Tunnel Man? It's time to explore the weird world of permafrost.
EXPLORE SOME MORE....
NOAA's Ark of Arctic Information
One of Alaska's permafrost ice science heroes is Vladimir E. Romanovsky, Associate Professor Geophysical Institute University of Alaska, Fairbanks. NOAA hosts his research and photos on their Arctic Theme Page.- CLICK HERE to read his overview of Alaska permafrost issues
- CLICK HERE to view an excellent permafrost photo gallery.
- CLICK HERE to visit NOAA's Arctic Theme Page.
- CLICK HERE to visit the National Snow and Ice Data Center
EXAMINE
- How does melting permafrost affect local hydrology?
- How does permafrost changes affect topography?
- What positive feedback systems accompany melting permafrost?
EXTEND
Teachers' Domain
People on the land see firsthand the changes in the Melting Permafrost.
YouTube 
CLICK HERE to if you're brave enough to visit Tunnel Man.
Teachers' Domain
People on the land see firsthand the changes in the Melting Permafrost.
YouTube
CLICK HERE to if you're brave enough to visit Tunnel Man.- Describe the connections between water in its various phases where you live.
What's Next?
Whew! You survived a lot of ice science and a visit with Tunnel man. Now we are prepared to discuss Climate Change and Human Migration.
